Alkyl(ene) polyalkylamines are well known and are used, inter alia, in asphalt applications.
WO 2006/076929 discloses, as intermediates in the synthesis of fully tertiary mono-fatty-alkyl polyalkylamines, a fully linear product with one fatty alkyl moiety. Although the reaction pathway is mentioned, the reaction conditions are not clear and the products, that have only one fatty alkyl moiety, seem to be pure. Salts of the fully tertiary mono-fatty-alkyl triamines are mentioned to be suitable for use in aqueous slow-setting bitumen-aggregate mixtures.
U.S. Pat. No. 4,967,008 relates to mono-fatty-alkyl polyalkylamines with primary, tertiary and optionally secondary amine moieties. An exemplified product is linear N-tallow-N-methyl dipropylene triamine. Because the intermediate in the process of U.S. Pat. No. 4,967,008 is methylated before the second cyanoethylation step, there is no branching in the products.
From CAS registration number 1623405-26-4, a linear di-fatty-alkyl tetramine with CAS-name “Amines, N′-{3-[(3-aminopropyl)amino]propyl}-N,N-di-C16-18 alkyltrimethylenedi-” is known.
US2003/049310 discloses a large amount of cationic lipids and the use thereof in liposomes to introduce functional bioactive agents to cultures cells. Mixtures of polyamines as claimed are not disclosed or suggested.
For lubricating oils a variety of amines have been evaluated in the past. Particular for 2-stroke marine engines it is known that due to changes in emission regulations, as well because of the different fuels used, there is a need for an improved amine formulation for use in lubricating oils, particularly for use in lubrication oils used in engines that burn sulfur-containing oils, particularly for lubrication of 2-stroke diesel marine engines.
Surprisingly it was found that compositions of di-fatty-alkyl(ene) tetramines with a specific amount of linear and branched molecules show excellent properties when used in lubrication oils and other applications where polyalkylamines are known to be used, such as in demulsifiers for oil-in-water emulsions, generic use as a corrosion inhibitor, fuel additive, anti-scaling agent, asphalt additive, enhanced oil recovery from oil-wells, cutting-oil additive, and anti-static agent. Furthermore, it was found that the claimed processes to make the di-fatty-alkyl(ene) tetramines is very economic in producing the desired compositions.
Accordingly, the invention relates to such di-fatty-alkyl(ene) polyalkylamine compositions which comprise mixtures of one or more polyalkylamines selected from products of the formulae (I) and (II)
wherein each R is, independent of the other R, a fatty-alkyl or fatty-alkylene moiety, herein defined as to have 8-22 carbon atoms, which is linear or branched, n and z are independent of each other either 0, 1, 2, or 3, and when z>0 then o and p are independent of each other either 0, 1, 2, or 3, or derivatives thereof, whereby said mixture comprises at least 3% by weight of branched products whereof at least one of n and z>=1. and whereby said mixture comprises at least 5% by weight of products with a pure linear structure. Such mixtures with both linear and branched products were found to have a desirable viscosity profile.
In an embodiment the amount of products with linear structure in the mixture is 6, 7.5, 10, or 14% by weight, or more, based on the weight of all polyalkylamines. In an embodiment the linear product in the mixture is of formula (I) with n and z being 0. In an embodiment the linear product in the mixture is of formula (II) with n is 0.
In an embodiment the mixtures comprise at least 4% by weight (′Yow/w), suitably at least 5% w/w, suitably at least 6% w/w, suitably more than 7% w/w, suitably more than 7.5% w/w, suitably more than 10% w/w, suitably more than 20% w/w, of branched compounds whereof, for the products of formula (I), at least one of n and z>=1, based on the weight of all polyalkylamines. For the products of formula (II) this means that for the branched products n must be >=1.
It is noted that whenever n, o, p, or z is 0 then the hydrogen is covalently bound to the nitrogen. For economic reasons each of n, o, p, and z, independently and when not 0, are 1 or 2, preferably 1.
Although the two R groups can be different, they are, in one embodiment, the same, since such materials are more economically produced. Irrespective of whether they are the same or not, one or both of the R groups, independently, are typically derived from chemical feedstock or from a natural source, such as from natural oils and fats. Particularly if a natural source is used, it means that each R group may have a certain distribution in the carbon chain length. Suitably R is derived from animal and vegetal oils and fats, such as tallow, coco and palm oil. Since making the di-fatty-alkyl(ene) polyalkylamines in accordance with the invention comprises a hydrogenation step, it may be beneficial to use hydrogenated R groups before the products of the invention are prepared using a process as claimed. However, for certain feedstocks, even after hydrogenization, an appreciable amount of unsaturated bonds may remain. Suitably a fully hydrogenated tallow group is used as the R group, and the corresponding mixture of di-fatty-alkyl polyalkyl amines are formed. Alternatively, the raw material for the R group is unsaturated whereby the unsaturated R group may be wholly or partially hydrogenated during the process to make the claimed di-fatty-alkyl(ene) polyalkylene amines being a mixture of di-fatty-alkyl polyalkylene amines and di-fatty-alkylene polyalkylene amines. Also products with one fully saturated R group and one unsaturated R group are products of the invention.
Therefore, as used herein, “di-fatty-alkyl(ene) polyalkylamines” refers to di-fatty-alkyl polyalkylamines, di-fatty-alkylene polyalkylamines, fatty-alkyl fatty-alkylene polyalkylamines, and mixtures thereof.
The term “consisting” wherever used herein also embraces “consisting substantially”, but may optionally be limited to its strict meaning of “consisting entirely”.
Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of the words, for example “comprising” and “comprises”, mean “including but not limited to”, and do not exclude other moieties, additives, components, integers or steps. Moreover the singular encompasses the plural unless the context otherwise requires: in particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
Where upper and lower limits are quoted for a property, for example for the concentration of a component, then a range of values defined by a combination of any of the upper limits with any of the lower limits may also be implied.
It should be appreciated that the various aspects and embodiments of the detailed description as disclosed herein are illustrative of the specific ways to make and use the invention and do not limit the scope of invention when taken into consideration with the claims and the detailed description. It will also be appreciated that features from different aspects and embodiments of the invention may be combined with features from different aspects and embodiments of the invention.
Derivatives of the di-fatty-alkyl(ene) polyalkylamines compositions of the invention include products wherein one or more of the NH moieties of the dialkyl polyalkylamines of the invention are methylated, alkoxylated, or both. Such products were found to have desirable solubility of the dialkyl polyalkylamines, particularly in lubricating oils. Alkoxylated derivatives are suitably butoxylated, propoxylated and/or ethoxylated. If two or more different alkoxylation agents are used then can be used in any sequence, e.g. EO-PO-EO, and the various alkoxy units can be of blocky nature and/or be present in a random fashion. Suitably a primary —NH2 group is alkoxylated with one or more alkylene oxides in a conventional way to form a —NH-AO-H group, wherein AO stands for one or more alkylene-oxy units. The resulting —NH-AO-H group can be further alkoxylated to form —N (AO-H)2 groups. Especially when large amounts of alkylene oxide (i.e. when more than 8 AO molecules per polyalkylamine molecule) are used, typically also one or more of the secondary amine functions, if present, are alkoxylated. In an embodiment all primary and secondary amine functions of the di alkyl polyamine are alkoxylated. In another embodiment the di-fatty-alkyl(ene) polyalkylamines are derivatized by methylating one or more of the N—H functions in a conventional way, for example by reaction with formic acid and formaldehyde. In another embodiment one or more of the O—H functions of an alkoxylated di-fatty-alkyl(ene) polyalkylamines is methylated in a conventional way.
Although the inventors do not wish to be bound by the following theory, it is believed that the beneficial properties of the dialkyl polyalkylamines compositions as claimed, when compared to the fully branched or fully linear products, lie in the special interaction of the amines in the composition. More specifically, the mixture of linear and branched products are believed to be the components for achieving the desired combination of rheological and anti-corrosion properties of the fluids in which the composition is used.
In view of this theory, it can be preferred to have products with a multitude of differently branched molecules. In that case, compositions comprising mixtures of polyalkylamines of the formula (I) are preferred. However, since compositions comprising mixtures of polyalkylamines of the formula (II) can be more economical to make, under specific circumstances compositions comprising mixtures of polyalkylamines of the formula (II) may be preferred. If suitable, compositions comprising mixtures of dialkyl(ene) polyalkylamines of the formulae (I) and (II) are used.
In one embodiment the invention relates to the use of a composition comprising both the branched products in combination with a linear product according to formula 1 wherein n and z are 0, which composition was found to also show the desired rheology and properties.
The claimed compositions are suitably used as demulsifier for oil-in-water emulsions, corrosion inhibition, fuel additive, anti-scaling agent, asphalt additive, enhanced oil recovery agent from oil-wells, cutting-oil additive, anti-static agent, and additive in lubricating oils, particularly in lubricating oils for machines with varying amounts of acidic, specifically sulfuric acid, contaminants. One particular interesting field of use is in 2-stroke marine diesel engines which are typically operated with different fuels, each with different sulfur content, depending on availability, price, and environmental regulations.
The dialkyl(ene) polyalkylamines mixtures as claimed can be produced using conventional process steps that are conducted in such order and way that the claimed mixtures are obtained. A suitable way to produce them is described in the experimental section below starting from a diamine and involving two or more cycles, for economic reasons preferably two, with each a cyanoethylation step and a hydrogenation step, hereinafter the two-cycle process. However, an alternative process wherein one equivalent of a di-alkyl-diamine is reacted in one step with two or more equivalents of acrylonitrile followed by hydrogenation, and optional further cycles involving a cyanoethylation and hydrogenation step, can be beneficial since it requires less reaction steps.
For increased branching in the two-cycle process, an acidic catalyst is used, such as HCl or acetic acid. Also increasing the reaction temperature during cyanoethylation will result in increased branching in this process. In an embodiment of a multicycle process, the temperature of a later cyanoethylation step is higher than the temperature in an earlier cyanoethylation step, to get a product with the desired branching. In an embodiment more than 1 mole of acrylonitrile is used per mole of the starting polyamine, which was also found to increase the branching of the resulting product to the desired level.
The temperature in each cyanoethylation step is suitably selected in the range from 70 to 125° C. In an embodiment the reaction is conducted, for economic reasons, at a temperature up to 80, 85, 90, 95, or 100° C.
For maintaining a homogeneous reaction mixture a solvent is suitably used. Suitable solvents include C1-4 alcohols and C2-4 diols. Ethanol may be a solvent of choice for ease of handling. Surprisingly the C1-4 alcohols and C2-4 diols were found not to be mere solvents. They turned out to also have co-catalytic activity in the cyanoethylation step.
The amount of solvent to be used can vary over a wide range. For economic purposes, the amount is typically kept at a minimum. The amount of solvent, particularly in a cyanoethylation step, is suitably less than 50, 40, 30, or 25% by weight of the liquid reaction mixture. The amount of solvent, particularly in a cyanoethylation step, is suitably more than 0.1, 0.5, 1, 5, or 10% by weight of the liquid reaction mixture.
The di-fatty-alkyl(ene) polyalkylamines compositions of the invention were found to be particularly suitable as a corrosion inhibitor, particularly in cutting-oils and lubricating oils. However, they are also suitably used as a demulsifier for oil-in-water emulsions, a fuel additive, an anti-scaling agent, an asphalt additive, an enhanced oil recovery agent for oil-wells, and as an anti-static agent.